干旱胁迫下长枝木霉对米槁幼苗生长和生理特征的影响

Effects of Trichoderma longibrachiatum on growth and physiological characteristics of Cinnamomum migao seedlings under drought stress

摘要:

背景 干旱会造成植被退化乃至死亡，木霉(Trichoderma spp.)则能通过一系列作用，包括促进根系生长发育、调控渗透调节物质的积累、激活植物自身的抗氧化系统等，有效提升植物对干旱环境的适应能力。目的 探究干旱胁迫下接种长枝木霉(Trichoderma longibrachiatum)对米槁(Cinnamomum migao H.W.Li)幼苗生长和生理特征的影响。方法 以米槁实生幼苗为材料，采取根际注菌的方式接种长枝木霉、设置4个水分梯度模拟干旱环境，研究其对米槁幼苗生长生理指标的影响。结果 长枝木霉显著促进根系发育，增加根平均直径和主根长，提升叶片相对含水量，降低水势，增强吸水能力；提高光合色素含量以增强光合效率，激活抗氧化酶活性、降低丙二醛含量以缓解氧化损伤；促进渗透调节物质积累，优化干物质分配，增加根冠比、茎生物量比及总生物量。Spearman相关性分析表明，长枝木霉改变了米槁生理指标的协同关系，形成更高效的干旱适应网络。结论 本研究为喀斯特干旱地区米槁栽培提供技术参考，显示长枝木霉在提升植物耐旱性方面的应用潜力。

Abstract:

Background Drought can cause vegetation degradation and even death, while Trichoderma spp. can effectively enhance plant adaptability to arid environments through a series of actions, including promoting root growth and development, regulating the accumulation of osmotic adjustment substances, and activating plant antioxidant systems.Objective To explore the effects of inoculation of Trichoderma longibrachiatum on the growth and physiological characteristics of Cinnamomum migao seedlings under drought stress.Methods We adopted the method of rhizosphere inoculation with T. longibrachiatum and set four water gradients to simulate drought conditions, thus investigating the effects on the growth and physiological characteristics of C. migao seedlings.Results T. longibrachiatum significantly promoted root development, increased the average root diameter and taproot length, raised the relative water content in leaves, reduced water potential, and enhanced water absorption capacity. Furthermore, it increased the content of photosynthetic pigments to enhance photosynthetic efficiency, activated antioxidant enzymes, and reduced malondialdehyde content to alleviate oxidative damage. In addition, this fungus promoted the accumulation of osmotic adjustment substances, optimized dry matter distribution, and increased the root/shoot ratio, stem biomass ratio, and total biomass. Spearman correlation analysis showed that T. longibrachiatum changed the synergistic relationship of physiological characteristics and formed a more efficient drought adaptation network.Conclusion This study provides a technical reference for the cultivation of C. migao in karst arid areas and shows the application potential of T. longibrachiatum in improving plant drought tolerance.